RESUMO
BACKGROUND: Toxoplasma gondii is a protozoan with worldwide distribution and triggers a strong Th1 immune response in infected susceptible hosts. On the contrary, most helminth infections are characterized by Th2 immune response and the use of helminth-derived antigens to regulate immune response in inflammatory disorders has been broadly investigated. OBJECTIVES: The aim of this study was to investigate whether treatment with Strongyloides venezuelensis antigen extract (SvAg) would alter immune response against T gondii. METHODS: C57BL/6 mice were orally infected with T gondii and treated with SvAg, and parasitological, histological and immunological parameters were investigated. RESULTS: It was observed that SvAg treatment improved survival rates of T gondii-infected mice. At day 7 post-infection, the parasite load was lower in the lung and small intestine of infected SvAg-treated mice than untreated infected mice. Remarkably, SvAg-treated mice infected with T gondii presented reduced inflammatory lesions in the small intestine than infected untreated mice and decreased intestinal and systemic levels of IFN-γ, TNF-α and IL-6. In contrast, SvAg treatment increased T gondii-specific IgA serum levels in infected mice. CONCLUSIONS: S venezuelensis antigen extract has anti-parasitic and anti-inflammatory properties during T gondii infection suggesting as a possible alternative to parasite and inflammation control.
